It is known that a motor vehicle door is generally held closed by a lock, the latch and pawl of which are arranged parallel to the edge of the door, the striker being secured to the bodywork pillar in the immediate vicinity of the edge of the door. The lock housing has a slot for the passage of the striker; the striker, when the door is closed, enters the fork of the latch, which pivots into a position in which it holds the striker which is kept in this position by the pawl. This well-known type of lock is always associated with a certain number of peripheral elements intended for operating the lock, namely, on the one hand, operating members for opening the door from the inside or from the outside of the passenger compartment and, on the other hand, locking and unlocking members which work from the inside or from the outside of the passenger compartment and, finally, safety members, for example a locking device that prevents the lock from being inadvertently opened by a child.
The presence of all these peripheral elements unfortunately causes locks of this type to have a complicated shape and means that the moving parts of the lock are arranged about pins which are parallel not only to the longitudinal axis of the vehicle, which is the case of the pawl and the latch, but also about pins parallel to the transverse axis and to the vertical axis of the vehicle. This therefore means that the locks have a complicated shape and given that the peripheral elements for operating the lock need to be protected against break-in, the locks need to have protective hoods of complex shape which are inconvenient for mounting the lock in the door; the more complex the shape of these hoods, the heavier and more expensive they become. Additionally is more though, locks of this type are extremely sensitive to sharp decelerations in the longitudinal direction of the vehicle because of the existence of the moving parts whose pins are perpendicular to the longitudinal axis of the vehicle. This means that these moving parts need, as a precaution, to be balanced by making some of their components heavier and subjecting them to springs. This then leads to an increase in the weight and cost of the lock.
Put another way, locks of the state of the art have the drawback of having bracket-shaped housings, the elements of which are not well able to withstand sharp decelerations in the event of an accident. The bracket shape resulting in that the cost and weight both of the structure of the constituent parts of the lock and of the hood are increased.
Obviously, it is highly desirable to produce a lock in which the housing could be more or less in the shape of a right-angled parallelogram, this lock then may have all of its elements in a plane perpendicular to the longitudinal axis of the vehicle.